Fuel pump



12, 1939.` A P, -THpms y 2,183,510

' FUEL PUMP FiledA Nov. l, 1937 Patented Dec. 12, 1939 f l lJNnlzD STATES 2,183,510 FUEL PUMP Alden P. Thomas, Canton, Ohio, assignor to The Tmken'Roller Bearing Company, Canton, Ohio,v

a corporation" of Ohio Application November 1, 1837, Serial No. 172.076 y15 claims. (c1. 10aa- 203iA This invention relates to pumps, particularly fuel pumps of the kind operated by or in unison with an internal combustion engine for supplying uid fuel to the charge forming device thereof.

It has `for its principal objects to provide a strong,

compact and durable oil-and air tight'pump ofsimple and economical construction, to facilitate assembly and disassembly of the parts, and to provide` separate,` readily. accessible manually operable means for priming the pump and clearing the fuel system of air. The invention consists inthe pump and in the construction, combinations and arrangements ofparts hereinafter described and claimed.

In vthe accompanying drawing, which forms part of this specification and wherein like symbols referto like parts wherever they occur,

Fig. 1 is a front elevation of a pump embodying my invention, the operating knob of the auxl) illary' pump piston being shown in locked position,

Fig. 2 is a similar View of the upper portion of the pump, showing saidA knob in unlocked position.

Fig. 3 is a central horizontal longitudinal section on-the-line 3--3 of Fig. 1; and

Fig. 4is avertical central longitudinal section on the line 4-4 in Fig. 1.

The pump shown in the accompanying drawing comprises a housing I having'a central horizontal bore 2 extending therethrough from front to.

lback thereof, whose front end is closed preferably by means of a threaded cap 3. Mounted in the front end portion of the' housing bore between an annular shoulder 4 therein and the cap or closure 3 for the front end thereof is a hollow cylindrical liner 5 having a wall 6 at the inner end thereof and a hollow stem 'l that projects axially from the rear face of said wall. This cupshaped' liner cooperates with the closed outer end of the housing bore.2 to form a pump chamber or cylinder 8for a piston 9.-.preferablyin the lform of. a. cup whose .open end faces theouter end of said cylinder. l Interposed between the outer `end of the pump cylinder 8- and the bottom of the cup-shaped piston 9 isa coil compression spring Ill, the ,expansive effectof which operates to force said piston Atowards the innerend of said cylinder. AThepiston isA moved in vthe opposite direction lby a pushrod or plunger. Il mounted for axialsliding movement in the rearwardly projecting hollow stem l of the 1iner.5 with one`-end ex. tendingdinto,v the rear endof the pump chamber 8 andloosvely connected to thev adjacent rear end liliv of vthe'gpivstonll. -This loose connection -preferf vend of` said bore.

ably comprises an undercut groove I2 in the inner end"wall`of the piston l.and a head. I3 on the adjacent end of said plunger tting in said groove.

Mounted vfor reciprocating movement in the I rear end portion of the pump housing bore 2 isl a tappet cup I4 whose open end faces the front The forward stroke of the tappet cup isproduced by a power operated tappet or edge 'cam I5; and the return stroke of A10 said cup is produced by the expansive effect of a coil spring I6 interposed between the end wall 6 of the liner 5'and a disk I'I having a convex surface disposed in abutting relation to the bottom or closed vend of said cup.A 15

The pump housing I has horizontally disposed, axially alined inlet and outlet passageways I8 and I9 therein disposed one on each side of the pump cylinder 8 and communicating with the inner end thereof through diametrically opposed 20 Ports Isa and Illa in .the liner 5. Said housing is also4 provided with a branchpassageway 20 that leads at van oblique angle from the'inlet passageway I8 and communicates with the outer end of the pump cylinder through a radial port 25 20a in the liner 5. The inlet passageway I8 is provided between its points of communication with its branch passageway 20 and said cylinder With an inwardly opening suction -or check valve in the form of. adisk 2| that seats against the 30 inner face of an annular hiember or washer 22 that is threaded into said passageway. This inlet valve 2l is yieldably held against its replaceable Vseating 22 by means of a compression coil spring A23 interposed between said Valve and an annular 35 shoulder 24 in said passageway. The outlet passageway I9 is provided with an outwardly opening check .valve in the form of a disk 25 that is yieldably held against an annular seating 26l in said passageway by a coilcompression spring 4,04

21 interposed between saidvalveand an annular member or washer 28 threaded into said outletv passageway outwardly of saidI valve.

'I'he hereinbefore described pump is also provided with a manually operable auxiliary pump 45.

ing` device comprising a piston 29 reciprocable in the axial bore 30 of anupright cylindrical extension Ia .of thepump housing I. The inner end of the? bore or` cylinder 30 communicateswith the innerend of the main pump cylinder. 8 50 through a radial port 3| in the liner'.A 5. The innerend Aof,l the auxiliarypiston 2911s provided with av gasket 32 adapted,in'the innermost posi--` tionfof said piston, to seaty against ran annular I shoulder 30a inthe-'bore 30 and thus cut offl com'- 55 munication between said bore and the main pump cylinder 8. The piston 29 is provided with an axially extending rod 33 that extends outwardly into the axial bore of a sleeve 34 that is'mounted' in said bore; and a coil compression spring 35 Y is interposed between said head and a Vknob 36 thatis threaded on the outer end of said sleeve.' vThe knob 36 is provided with a peripheral skirt' or flange 31 that enclosesthe outer end portion of the radial extension Ia of the pump housing and has a bayonet notch 38 in the/lower edge thereof adapted to engage a pin 39 that extends radially through the wall of said extension with its outer end in position to enter said notch by the rise of the cam I5, the plunger II forces the piston 9 outwardly in the cylinder 9. This outward movement of the piston draws fuel into the cylinder through the inwardly opening suction or inlet valve 2| while the outwardly opening outlet or discharge valve remains closed. When the drop of the cam I5 is in engagement with the tappet cup, the spring I3 forces said cup rearwardly, thereby releasing the pressure of the plunger on the inner end of the piston 9 and thus permitting said piston to be forced inwardly in its cylinder by the spring I0. This rearward or inward movement of the piston 9 forces the fuel in the inner end of the cylinder 8 through the outlet valve 25 and thence through the outlet passageway I9 to the injection pump or other charge forming device of the engine. The forward or front end ofthe cylinderis always supplied by the branch 20 of the inlet passageway with fuel which surges back and forth between the piston 9 .and said inlet passageway during the reciprocating movement of the piston, thereby preventing the piston from sucking air on its suction stroke and returning to said inlet passageway any fuel that may leak past the piston during the delivery stroke thereof.

When it is desired to prime or flush the pump. the operating knob 36 is released from the hold down pin 39 therefor and the auxiliary piston 29 is reciprocated to draw fuel through the inlet valve 2| into the main pump chamber 8 and then discharge said fuel through the outlet valve 25 thereof. The inward motion of the knob 36 is transmitted to the piston rod 33 through the spring 35, while the outward movement of said knob is transmitted to said rod by the engagement of the shoulder 34a in the rod receiving bore of said sleeve with the underside of the head- 33a at the outer end of said rod. The pin 39, which cooperates` with the slot 34h in the sleeve 34, serves to limit the sliding movement of said sleeve in both directions. InV the innermost or locked position of the knob, the spring exerts considerable downward pressure on the piston rod 33 and thus serves to hold the piston 29 in tight sealing engagement with the shoulder 30a in the bore 3U so as to prevent leakage of air to the fuel system.

The hereinbefore described pump has several' advantages. The inlet and outlet valves are close to the pump cylinder and the inlet and outlet passageways are short and straight and open directly into the cylinder at diametrically opposite points. The suction stroke is imparted to the piston entirely by the cam and the discharge stroke is imparted to said piston by the spring only, thereby securing a more positive pumping action. The filling of the cylinder through the inlet valve on the suction stroke is facilitated by the displacement by said piston of fuel in the spring chamber of the cylinder back into the inlet passageway. This forcing of such fuel into theA inlet passageway assists the inlet valve in opening and also assists the piston in obtaining an adequate supply of fuel from said inlet passageway. Any leakage past the piston from the high to the low pressure side of the cylinder is returned directly into the intake passageway, and this low pressure side of the cylinder is constantly ll'ed with fuel which prevents the piston from sucking air on its suction stroke.

While I have described my pump for use as a supply pump for a fuel feed system of an internal combustion engine, it is obviously adapted for other uses.

What I claim is:

1. A pump comprising a housing having a cylinder, inlet and outlet passageways communicating directly with the same end of said cylinder and a valveless branch passageway in continuous communication with said inlet passageway and the other end ofsaid cylinder, a piston reciprocable in said cylinder, and an inwardly opening check valve in said inlet passageway between said cylinder and the point of communication of said inlet passageway with said branch passageway.

2. A pump comprising a.housing having a cylinder, inlet and outlet passageways communicating directly with the same end of said cylinder an'd a valveless branch passageway communicating with said inlet passageway and the other end of said cylinder, a piston reciprocable in said cylinder, a check valve in said outlet passageway. and an inwardly opening check valve in said inlet passageway between said cylinder and said branch passageway.

3. A pump comprising a housing having a cylinder, diametrically opposed inlet and outlet passageways communicatingdirectly with said cylinder adjacent to the same end thereof and a valveless branch passageway communicating with said inlet passageway' and with said cylinder adjacent to the other end thereof, a piston reciprocable insaid cylinder, a check valve in raid outlet passageway,- and an inwardly openingcheck valve in said inlet passageway between said cylinder and saidb'ranch passageway.

4. A pump comprising a' housing having a cylinder, inlet and outlet passagewayscommunicating directly with the same end ot said cylinder at diametrically opposite points and a valveless branch passageway leading from said inlet passageway to the other end of said cylinder, a piston -reciprocable in said cylinder, a check valve in said inlet passageway between said cylinder and said branch passageway, power operated lmeans for moving said piston in a direction that -spring means for moving saidpiston in the opposite direction to discharge iluid through said outlet passageway.

. 5.' A pump comprising ahouslng -having a cyl-v inder, inlet and outlet passageways communicating directly with the -s'amelend of said cylinder i at diametrically opposite pointsand a valveless branch passageway leading from said inlet'passageway to the other end of said cylinder, a piston reciprocable in said cylinder, an inwardly opening check valve in said inletpassageway between said cylinderand s'aid branch passageway, a check' valve in said cutlet passageway, power operated means for moving said piston in adirect'ion'that'will draw fluid from saidinlet passageway into said first mentioned end of said cylinder,

and force iluid in said other end of said cylinder and-said. branch passageway into said inletpassageway, and spring means for moving said piston y in the opposite direction -to discharge fluid through saidsoutlet passageway and to draw iluid.

t into said'other' end of said cylinder through said inlet branch passageway.

6. A pump ycomprising a housing having a cylinder, inlet and outlet passageways communicatv`inder for moving saidpiston in the` opposite direction to discharge said duid through the check valve in saidv outlet eway,'said power operated means including a plungerreciprocable in said housing and having a connection with said piston adaptedto accommodate misalinement of said piston and said push rod.

7. A pump comprisinga body having a cylin-` vdrical bore therein, a removable closure for said 4bore, a hollow cylindrical liner in said bore having at the end remote from said closure an end wall which has a hollow stem projecting axially 50- therefrom on the side' thereof remote from said closure, a piston reciprocable'in said liner be-i .tween the end wall thereof and said closure, Ain-4 A s" reciprocable in said'hollow stem vand operatively l let and outlet passageways communicating with` the interior of said liner, a spring interposed between said closure andsaid piston, anda plunger engaging the adjacent end of said piston.

. 8. Afpump comprising a body having a cylindrical bore. therein, a removable closure for said ybore, a hollow cylindrical liner in said bore having at the end remote-from said .closure au` end therefr on the side thereof remote from said vclosure a piston reciprocable in'said-linerbei -wall wlih has a hollowl stein projectingfaxially tween end wallA thereof and said'closureinlet and\1itletpassageways both communicating th the interior of said liner adjacent directly A to the eixxd wall thereof, a spring interposed between sa d closure and said piston, a-plungerrecipropable insaidv hollow'stem and operatively,

engaging the adjacent end of said piston, said inlet passageway having a branch in continuous communication with theinterior of said liner adjacent to the closure opposing end thereof. and .an inwardly opening check valve in said'inlet,

passagewayfbetween its points of communication with said liner and said .branch passageway.-

9. A pump comprising a body having a cylindrical bore therethrough. a removable closure for v said bore,va hollow cylindrical liner removably mounted in said bore and' having at the end remote from said closure an end wall whichhas a hollow stemy projecting axially therefrom on the ,side thereof remote from said closure, a piston reciprocable in said liner between the end lwall thereof and said` closure, inlet and outlet passageways communie ting with the interior oi said liner, a spring inte osed between said closure and saidpiston, and a plunger reciprocable in said hollow stem and operatively. engaging the adjacent end of saidfpiston, said :plunger ha'vlng a connection withsaid piston adapted to accommodate misalinement of said piston and said*V splunger.

. 10. A pump comprising a body having a cylln- 1 drical ,bore therein, a removable closure for said bore, a hollow cylindrical liner in said bore' and i having at the end remote from said closure `an j end wall'which has a hollowstem projecting axially -therefrom on the side thereof remote from said closure, a piston reciprocablein said liner between Ithevend wall thereof andssaiii closure, inlet and outlet passageways communicat- -ing with the interior 'of said liner, a check valve insaid outlet port, a spring located in said liner between' said clo'sure and said piston, a plunger reciprocable in said hollow stem and connected to the adjacent end of said piston, said inlet and i' l outlet passageways each communicating with the- II to said end wall thereof, and said inlet passage- I interior of said liner-at points located adjacent way having a valveless branch communicating closure opposing end thereof, anda check valve in said inlet passageway between said liner I and sa'id branch passageway.

l1. Av pump comprising a housing a cylinder, inlet and outlet eways communi- ".cating with one Aend of said cylinder, a-piston reciprocable in said cylinder', and a check valve in said inlet eway, said housing havinga second cylindertherein 'opening into said endV of said ilrst mentionedA cylinder, and a 'manually operable piston reciprocable in saidsecond cylinder.

l i2. A pump comprising a housing having a cyiinder, inlet and outlet passageways communi-i' with the interior of said nner adjacent to the v eating with one end of said Acylinder and abranch passageway communicating with lsaid inlet passagewayand the other end of said cylinder', a' v .455 -valve in said inlet Apassageway between saidcyipiston reciprocable in said cylinder, and 'a check inder and said branch passageway, said housing having a second cylinder therein opening into said first mentioned end of said first mentioned cylinder. .and a.manually operable piston recipro'cable in said second cylinder.

13. A pump comprising a body having ,a cylindrical boretherein, a removable closure for I said bore, a hollow cylindrical liner in said-bore` having at lthe en d remote from lsaldclosure an end wall with a hollow stem projecting from the side thereof remote from 'said closure,a piston reciprocable in said liner between the end wall thereof and saidl closure, inlet and outlet passageways communicating withthe interior of said liner adjacent to the en d wall thereof, a checkA valve in said outlet port, a spring interposed between said closure and said piston. a plunger reciprocatingin saga hollow stem and operatively connected' to the adjacent end of said piston. a branch passageway communicating with said inlet passageway and the interior of said liner adjacent t0 the closure opposing end thereof, a check valve in said inlet passageway between said liner and ,said branch passageway, said body having a secoperable piston reciprocable in said second cylinder, said second cylinder having a seat therein for the inner end .of the piston therein, and releasable means for holding said end of said piston against said seat.

15. A pump comprising a housing having a cylinder and inlet and outlet passageways communicating with one end of said cylinder, a piston reciprocable in said cylinder, a second' cylinder opening into said end of said iirst mentioned cylinder and having an annular shoulder. formed therein adjacent to the inner end thereof, a piston in said second cylinder adapted in its innermost position to seat against said annular shoulder and cut oil communication between said cylinders, a sleeve reciprocable in the outer end portion of said second cylinder, a rod iixed to the piston in said second cylinder and extending outwardly therefrom intosaid sleeve. a'knob iixed to the outer end of said sleeve, a spring mounted in said sleeve between said knob and the outer end of said rod, and means for locking said knob to the 'pump housing in the innermost position of said sleeve, whereby said spring is placed under compression and operates to hold the piston in said second cylinder against the annular shoulder therein.-

AL'DEN P. THOMAS. 

